Cold fusion

This article is about the nuclear reaction. For the computer programming language, see ColdFusion.
Charles Bennett examines three "cold fusion" test cells at the Oak Ridge National Laboratory, USA
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Charles Bennett examines three "cold fusion" test cells at the Oak Ridge National Laboratory, USA

Cold fusion is a name for any nuclear fusion reaction that occurs well below the temperature required for thermonuclear reactions (which occur at millions of degrees Celsius).

There are a number of suggested processes by which this might occur, although currently none of these has been proven to produce more energy than is required to sustain the reaction.

The term is often used in a more narrow sense: that is, a phenomenon observed in electrolytic cells in which a small (table-top) apparatus near room temperature and standard atmospheric pressure has been suggested to be the fusion of hydrogen (specifically deuterium) atoms into helium.

Additional claims are now made in the cold fusion field, in addition to the fusion reaction. For this reason, the terms "Low Energy Nuclear Reactions" and "Condensed Matter Nuclear Science" are also used to describe work in this field.

Nuclear fusion using deuterium (an isotope of hydrogen) yields large amounts of energy, uses an abundant fuel source, and produces only small amounts of radioactive waste. Therefore, a cheap and simple process of nuclear fusion would have great economic impact. As of 2005, however, hot fusion cannot be achieved in a controlled and sustained way, and proven cold fusion methods do not seem to yield more energy than is put into them. If cold fusion in electrolytic cells were to be proven, it might become a cheap and simple means of power generation.

Contents

History

Early work

Palladium and titanium have a proven ability to absorb large quantities of hydrogen. Although the distance between hydrogen nuclei suspended in such metals is no less than it is in other situations (such as a molecule of water), it has been suggested that these metals might, by bringing the deuterium atoms close together, catalyze the fusion of deuterium at ordinary temperatures.

The special ability of palladium to absorb hydrogen was recognized in the 19th century. In the late 1920s, two German scientists, Fritz Paneth and Kurt Peters, reported the transformation of hydrogen into helium by spontaneous nuclear catalysis when hydrogen is absorbed by finely divided palladium at room temperature. These authors later acknowledged that the helium they measured was due to background from the air or the glassware they used.

In 1927, Swedish scientist John Tandberg said that he had fused hydrogen into helium in an electrolytic cell with palladium electrodes. On the basis of his work he applied for a Swedish patent for "a method to produce helium and useful reaction energy". After deuterium was discovered in 1932, Tandberg continued his experiments with heavy water. Due to Paneth and Peters' retraction, Tandberg's patent application was eventually denied.

Pons and Fleischmann's experiment

On March 23, 1989, the chemists Stanley Pons of the University of Utah and Martin Fleischmann of the University of Southampton ("P and F") held a press conference and reported the production of excess heat that could only be explained by a nuclear process. The report was particularly astounding given the simplicity of the equipment, just a pair of electrodes connected to a battery and immersed in a jar of heavy water (dideuterium oxide). The press reported on the experiments widely, and it was one of the front-page items on most newspapers around the world. The immense beneficial implications of the Utah experiments, if they were correct, and the ready availability of the required equipment, led scientists around the world to attempt to repeat the experiments within hours of the announcement.

The press conference followed about a year of work of increasing tempo by Pons and Fleischmann, who had been working on their basic experiments since 1984. Their collaboration goes back even further than this, however. Pons had been a graduate student of Fleischmann's at the University of Southampton. In 1988 they applied to the US Department of Energy for funding for a larger series of experiments: up to this point they had been running their experiments "out of pocket".

The term "cold fusion" was coined by Dr Paul Palmer of Brigham Young University in 1986 in an investigation of "geo-fusion", or the possible existence of fusion in a planetary core. The term was then applied to the Fleischmann-Pons experiment in 1989.

The grant proposal was turned over to several people for peer review, including Steven Jones of Brigham Young University. Jones had worked on muon-catalyzed fusion for some time, and had written an article on the topic entitled "Cold Nuclear Fusion" that had been published in Scientific American in July 1987. He had since turned his attention to the problem of fusion in high-pressure environments, believing that fusion in the metallic hydrogen core of Jupiter might be responsible for the higher than normal temperatures of that planet. Paul Palmer noted that the same mechanism might explain the high interior temperature of the Earth (hotter than could be explained without nuclear reactions), and the unusually high concentrations of helium-3 around volcanoes, which implied some sort of nuclear reaction within. Jones started studying high-pressure fusion, which he referred to as piezonuclear fusion, by working with diamond anvils; but he had since moved to electrolytic cells similar to those being worked on by Pons and Fleischmann. In order to characterize the reactions, Jones had spent considerable time designing and building a neutron counter, one able to accurately measure the tiny numbers of neutrons being produced in his experiments.

Both teams were in Utah, but did not know of each other's work until the peer review. After that, they met on several occasions to discuss sharing work and techniques. During this time Pons and Fleischmann described their experiments as generating considerable "excess energy", excess in that it could not be explained by chemical reactions alone. If this were true, their device would have considerable commercial value, and should be protected by patents. Jones was measuring neutron flux instead, and seems to have considered it primarily of scientific interest, not commercial. In order to avoid problems in the future, the teams apparently agreed to simultaneously publish their results, although their accounts of their March 6 meeting differ.

In mid-March both teams were ready to publish, and Fleischmann and Jones were to meet at the airport on March 24 to both hand in their papers at the exact same time. However Pons and Fleischmann then "jumped the gun," and held their press conference the day before. Jones, apparently furious at being "scooped," faxed in his paper to Nature as soon as he saw the press announcements. The rush to publish perhaps did as much to muddy the field as any scientific aspects.

Within days scientists around the world had started work on duplications of the experiments. On April 10 a team at Texas A&M University published results of excess heat, and later that day a team at the Georgia Institute of Technology announced neutron production. Both results were widely reported on in the press. Not so well reported was the fact that both teams soon withdrew their results for lack of evidence. For the next six weeks competing claims, counterclaims, and suggested explanations kept the topic on the front pages, and led to what writers have referred to as "fusion confusion."

On April 12 Pons received a huge standing ovation during his presentation at the semi-annual meeting of the American Chemical Society. In May, the president of the University of Utah, who had already secured a $5 million commitment from his state legislature, asked for $25 million from the federal government to set up a "National Cold Fusion Institute". On May 1st a meeting of the American Physical Society held a session[1] (http://www.ibiblio.org/pub/academic/physics/Cold-fusion/vince-cate/aps.ascii) on cold fusion that ran past midnight; a string of failed experiments were reported. A second session started the next evening and continued in much the same manner. To some degree this reflected a split between the "chemists" and the "physicists", though it also reflected a more general change in opinion during the weeks which passed between the meetings. Skepticism of the cold fusion claims was rising among both chemists and physicists as more experimentalists attempted and were unable to replicate the experiment.

At the end of May the Energy Research Advisory Board (a standing advisory committee in the US Department of Energy) formed a special panel to investigate cold fusion. The report of the panel after five months' study was that there was no convincing evidence for cold fusion, and that such an effect "would be contrary to all understanding gained of nuclear reactions in the last half century." It specifically recommended against any special funding for cold fusion research, but was "sympathetic toward modest support for carefully focused and cooperative experiments within the present funding system". [2] (http://www.ncas.org/erab/sec5.htm)

Both critics and those attempting replications were frustrated by what they said was incomplete information released by the University of Utah. With the initial reports suggesting successful duplication of their experiments there was not much public criticism, but a growing body of failed experiments started a "buzz" of its own. Pons and Fleischmann later apparently claimed that there was a "secret" to the experiment; on the other hand, Fleischmann said at a meeting in April that all the necessary details had been given in the published paper. The facts here are not clear; but if such data had been withheld, the report would have been outside the field of modern science, and scientists would have been justified in dismissing the matter out of hand.

By the end of May much of the media attention had faded among the competing results and counterclaims. More significantly, the research effort decreased greatly as most attempts at replication failed and none produced definitive results. Nonetheless, projects continued around the world.

Experimental set-up and observations

Missing image
Cold_fusion_electrolysis.PNG
Fleischmann and Pons reported more energy coming from their electrolysis cell than they contributed.

In their original set-up, Fleischmann and Pons used a Dewar flask (a double-walled vacuum flask) for the electrolysis, so that heat conduction would be minimal on the side and the bottom of the cell (only 5% of the heat loss in this experiment). The cell flask was then submerged in a bath maintained at constant temperature to eliminate the effect of external heat sources. They used an open cell, thus allowing the gaseous deuterium and oxygen resulting from the electrolysis reaction to leave the cell (with some heat too). It was necessary to replenish the cell with heavy water at regular intervals. For the temperature observations to be meaningful the cell must be kept at a uniform temperature. Rather than using a mechanical method of stirring, sparging with the generated D2 gas was done to equalize the temperature "when necessary"; however, the efficacy of this method of maintaining the cell at a uniform temperature would later be disputed. Special attention was paid to the purity of the palladium cathode and electrolyte to prevent the build-up of material on its surface, especially after long periods of operation.

The cell was also instrumented with a thermistor to measure the temperature of the electrolyte, and an electrical heater to generate pulses of heat and calibrate the heat loss due to the gas outlet. After calibration, it was possible to compute the heat generated by the reaction.

A constant current was applied to the cell continuously for many weeks, and heavy water was added as necessary. For most of the time, the power input to the cell was equal to the power that went out of the cell within measuring accuracy, and the cell temperature was stable at around 30 °C. But then, at some point (and in some of the experiments), the temperature reportedly rose suddenly to about 50 °C without changes in the input power, for durations of two days or more. The generated power was calculated to be about 20 times the input power during the power bursts. Eventually the power bursts in any one cell would no longer occur, and the cell was turned off.

Pons and Fleischmann also initially reported that a cell was generating 2.45 MeV neutrons at a rate three times the natural background rate. There was, however, no equipment directly measuring neutron energies, and this report was based on a mistaken inference from a gamma-ray spectrum. The most spectacular result they reported was that in one cell the most of the electrode melted and part of it vaporized, destroying the cell and the fume hood enclosing it.

In the months after the initial report went public, a physicist colleague of Pons at the University of Utah, Michael Salomon, was invited into Pons' laboratory. In the five week period he and his research group observed the cells, no fusion products were detected. Pons stated that none of the cells were actively producing the excess heat at the time those observations were taking place, except during one two-hour period during which the detection equipment was unable to function because of a power failure. As neutron irradiation would produce small amounts of 24Na in the detector, Salomon quickly performed an analysis for that product, and found no amount consistent with power production of more than one microwatt. When Salomon and his co-workers had published their results in the journal Nature, each of them received a letter from attorney C. Gary Triggs, declaring that the "paper as published was untenable" and that it should be "voluntarily retracted." Triggs had, he said, been instructed by his clients "to take whatever action is deemed appropriate to protect their legal interests and reputations." Salomon and other scientists, perceiving this as an unprecedented threat against open scientific controversy, rejected the claims categorically and angrily; later, the threats were largely withdrawn.

Continuing efforts

There are still a number of people researching the possibilities of generating power with cold fusion. Scientists in several countries continue the research, and meet at the International Conference on Cold Fusion (see Proceedings at [3] (http://www.lenr-canr.org/index.html)).

The generation of excess heat has been reported by

among others. In the best experimental set-up, excess heat was reported in 50% of the experiment reproductions. Various fusion ashes and transmutations were reported by some scientists.

Dr. Michael McKubre thinks a working cold fusion reactor is possible. Dr. Edmund Storms, a former scientist with The Los Alamos National Laboratory in New Mexico, maintains an international database of research into cold fusion.

In March, 2004, the U.S. Department of Energy (DOE) decided to review all previous research of cold fusion in order to see whether further research was warranted by any new results. The review document[4] (http://www.newenergytimes.com/reports/DOE/2004-DOE-Summary-Paper.pdf) submitted to the DOE by the group of scientists who had requested a new review process states that "The experimental evidence for anomalies in metal deuterides, including excess heat and nuclear emissions, suggests the existence of new physical effects". It recognizes indirect evidence in support of the D + D → 4He + 23.8 MeV (heat) reaction, although the measurement of 4He quantity is imprecise. This review document was submitted to peer review, to a mixed but predominantly negative response. Of the 18 reviewers, "Two-thirds of the reviewers commenting on Charge Element 1 did not feel the evidence was conclusive for low energy nuclear reactions, one found the evidence convincing, and the remainder indicated they were somewhat convinced. Many reviewers noted that poor experiment design, documentation, background control and other similar issues hampered the understanding and interpretation of the results presented." [5] (http://www.science.doe.gov/Sub/Newsroom/News_Releases/DOE-SC/2004/low_energy/CF_Final_120104.pdf)

In 2004, Mike McKubre of SRI International reported that the effect is highly dependent on the packing of deuterium in the electrode. He reports that with a deuterium/palladium ratio of 100% (i.e., one deuterium atom for each palladium atom) excess heat is consistently produced, whereas at a ratio of 90% only two experimental runs in 12 show excess heat. Should the effect turn out to be reproducible (which is not yet established in 2004), it should be possible to make experiments that will show definitely whether the heat is due to chemical effects, cold fusion, or some form of energy storage.

As of 2004 the excess heat phenomenon remains unexplained, and the reported energy output has never been associated with an equivalent amount of fusion products of any kind. Although there may be a genuine physical phenomenon at work, the theory that it involves nuclear fusion is unproven and widely seen as unlikely. Less exotic theories have been proposed, but also remain unproven. After sixteen years of investigation, study continues, and investigators are hopeful that the phenomenon will be understood in a matter of years.

In 2005, scientists at UCLA used a pyroelectric crystal heated from -30 to 45 degrees Fahrenheit to produce an electric field of about 100,000 volts, forcing hydrogen nuclei together to produce helium nuclei, as well as other tell-tale signs of fusion, such as free neutrons and high energy radiation. This experiment has been repeated successfully, and other scientists have confirmed the results. Currently, the experiment still requires more energy than it produces. [6] (http://rodan.physics.ucla.edu/pyrofusion/) [7] (http://www.nature.com/nature/journal/v434/n7037/suppinfo/nature03575.html) [8] (http://www.christiansciencemonitor.com/2005/0606/p25s01-stss.html) [9] (http://msnbc.msn.com/id/7654627)

Arguments in the controversy

The vast majority of scientists consider current cold fusion research to be pathological science, while proponents argue that they are conducting valid experiments that challenge mainstream science (see history of science and technology). Here are the main arguments in the controversy:

Experimental design

One of the main criticisms of the cold fusion claims is that the experimental design made it very difficult to get reliable and repeatable results. In particular, there are many different ways by which the experiment can exchange energy with its environment, and the book-keeping necessary to establish whether or not there is any net energy gain has been criticized for being difficult to do correctly and prone to error.

This objection could be overruled either by creating an experiment which is less subject to errors, or by looking for signs of fusion which have nothing to do with excess heat. Neither of these strategies has produced conclusive evidence that this cold fusion process exists.

Reproducibility of excess heat

While some researchers claimed to have reproduced the excess heat with similar, or different, experiments, they could not do it with predictable results, and many others failed to measure excess heat.

However, it is not uncommon for a new phenomenon to be difficult to control, and to bring erratic results. For example, attempts to repeat electrostatic experiments (similar to those performed by Benjamin Franklin) often fail due to excessive air humidity. That does not mean that electrostatic phenomena are fictitious, or that experimental data are fraudulent. On the contrary, occasional observations of new events, by qualified experimenters, can in some cases be the essential steps leading to recognized discoveries. At the same time, it is also the case that experiments are hard to do, and it is easy to come up with results which look anomalous but which are in fact the result of experimental design deficiencies.

The reproducibility of the result will remain the main issue in cold fusion research until an experiment is designed which is fully reproducible by following a clear recipe, and which preferably generates power continuously rather than sporadically and does so in a way that cannot be attributed to experimental defects. As of 2004 this issue may have been resolved by the work of Mike McKubre at SRI International.

Lack of expected decay products

Even in the face of inconsistent evidence regarding the production of heat, cold fusion could be established by observation of decay products which are specific only to fusion. According to conventional fusion theory, if the excess heat were generated by the fusion of 2 deuterium atoms, the most probable outcome would be the generation of either a tritium atom and a proton, or a 3He and a neutron. The level of neutrons, tritium and 3He reported from the Fleischmann-Pons experiment was well below the level expected in view of the heat reported—such a neutron flux would in fact have been lethal—implying that these fusion reactions cannot explain it. Researchers in the cold fusion field claim that 4He is the dominant by-product of cold fusion. In conventional fusion, less than 1% of the nuclear products are seen as 4He.

References

1. Miles, M., "Correlation of Excess Enthalpy and Helium-4 Production: A Review," Tenth International Conference on Cold Fusion, Cambridge, Mass., (2003) http://newenergytimes.com/Library/2003MilesM-ICCF-10-Correlation-Of-Excess.pdf

2. Bush, Benjamin F., et al., "Helium Production during the Electrolysis of D2O in Cold Fusion Experiments," J. Electroanal. Chem., 304, (1991), p. 271 http://newenergytimes.com/Library/1991BushB-HeliumProductionDuringTheElectrolysis.pdf

3. De Ninno, Antonella, et al., "Experimental Evidence of 4He Production in a Cold Fusion Experiment," ENEA - Unità Tecnico Scientifica Fusione, Centro Ricerche Frascati, Roma, (2002) http://newenergytimes.com/Library/2002DeNinnoA-ExperimentalEvidenceOf4HeProduction.pdf

4. Gozzi, D., et al., "X-ray, Heat Excess and 4He in the D:Pd System," Journal of Electroanalytical Chemistry 452, (1998) http://www.newenergytimes.com/library/1998GozziD-HeGozziDxrayheatex.pdf

A larger collection of related papers on helium evolution is here: http://newenergytimes.com/Reports/Heat&NuclearProductCorrelation.htm


It should also be noted that none of the other processes termed cold fusion have these theoretical issues. In particular, the Farnsworth-Hirsch Fusor is sold commercially as a source of neutrons, and evidence for some of the other forms of fusion comes not from excess heat but from the decay products.

This experimental result could be and has been explained by arguing that the current understanding of physics is incorrect, but this leads to other problems.

Current understanding of physics

In addition to the lack of decay products, current understanding of nuclear fusion shows that the following explanations are not adequate:

  • Nuclear reaction in general: The average density of deuterium in the palladium rod seems vastly insufficient to force pairs of nuclei close enough for fusion to occur according to mechanisms known to mainstream theories. The average distance is approximately 0.17 nanometers, a distance at which the attractive strong nuclear force cannot overcome the Coulomb repulsion. Actually, deuterium atoms are closer together in D2 gas molecules, which do not exhibit fusion.
  • Fusion of deuterium into helium 4: if the excess heat were generated by the fusion of two deuterium atoms into 4He, a reaction which is normally extremely rare, gamma rays and helium would be generated. Again, insufficient levels of helium and gamma rays have been observed to explain the excess heat, and there is no known mechanism to explain how gamma rays could be converted into heat.

Disagreement with existing theory does not in itself prove that the experiment is wrong. For example, both superconductivity and Brownian motion were observed (and could be reproduced by anyone with suitable equipment) long before they were explained; high-temperature superconductivity has yet to be explained, despite the industrial availability of such superconductors. On the other hand, one can also cite observations of polywater and N-rays. Only four or five researchers claimed they reproduced these effects, and they claimed the signal to noise ratio was very low. [1] [2]. In contrast, hundreds of researchers worldwide claim they have reproduced cold fusion, often at very high signal to noise ratios. Excess heat has been measured at sigma 50 to 100, and tritium between 60 and 1 million times background. Roughly 500 papers were published about polywater at the peak, but most were theory and only a handful claimed positive results, whereas over 3,000 papers on cold fusion have been published.

Although requiring exotic or unknown physics does not rule out the existence of a process, it does drastically increase the level of evidence needed to establish a process, while at the same time making it much harder to perform experiments to verify that the process exists. Requiring exotic or unknown physics increases the suspicion that the underlying cause of the experimental results lies in errors of experimental design or misinterpretation of results, and causes the scientific community to be skeptical of marginal results and demand unambiguous demonstrations of a process.

At the same time, lack of an adequate theory makes it much harder to design experiments to create those results. Without such theory, it is much more difficult to predict what could happen in a given situation and design experiments to test those predictions. For example, based on standard nuclear theory, one would expect that the amount of heat generated would depend on the concentration of heavy water or the ratio between deuterium and tritium. These relationships do not appear to hold consistently, and the inability to establish any definite relationships between the energy output of the experiments and experimental inputs leads to skepticism that what is being observed has anything to do with fusion.

Most people still define "cold fusion" as a phenomenon in which "heat is produced from fusion of isolated deuterium nuclei at ordinary temperatures." It is not difficult to be convinced that such phenomenon is impossible. This has nothing to do with chemically assisted nuclear anomalies in condensed matter reported in recent years. This refers, for example, to emission of neutrons, at rates too small to release measurable amounts of heat. It also refers to generation of helium and tritium, to unusual isotopic ratios, and to nuclear transmutations in deuterized metals. The second DOE review (December, 2004) recognizes "a number of basic science research areas that could be helpful in resolving some of the controversies in the field, two of which were: 1) material science aspects of deuterated metals using modern characterization techniques, and 2) the study of particles reportedly emitted from deuterated foils using state-of-the-art apparatus and methods."

1. Klotz, I., The N-Ray Affair. Scientific American, 1980. 242(5): p. 168-175. 2. Franks, F., Polywater. 1981, Cambridge, MA: MIT Press.

Energy source vs power store

Some skeptics claim that while the output power is higher than the input power during the power burst, the power balance over the whole experiment does not show significant imbalances. Since the mechanism under the power burst is not known, one cannot say whether energy is really produced, or simply stored during the early stages of the experiment (loading of deuterium in the Palladium cathode) for later release during the power burst. A "power store" discovery would yield only a new, and very expensive, kind of storage battery, not a source of abundant cheap fusion power.

Cold fusion researchers disagree. They point out that in all experiments in which excess heat has been recorded, the overall balance has been positive; there are no instances in which a heat deficit was recorded first, that would balance out the excess. In most bulk palladium electrochemical experiments, an incubation period of 10 to 20 days is followed by continuous excess heat production, which often continues longer than the incubation period. Ref 1 shows typical examples. Since the excess heat is easily detected, at a high signal to noise ratio, and the initial deficit would have to be even larger than the excess that follows, it would easily be detected. Researchers also point out that most cells produce far more energy than any known chemical storage mechanism would permit. Chemical processes store (or produce) at most 12 eV per atom of reactant, whereas many cold fusion experiments have produced hundreds of eV per atom of cathode material, and some have produced ~100,000 eV per atom.

Furthermore, many researchers, notably Kainthla et al. [2] and McKubre et al. [3] have conducted careful inventories of chemical fuel and potential storage mechanisms in cold fusion cells, and they have found neither fuel nor spent ash that could account for more than a tiny fraction of the excess heat. Since many cells have released large amounts of energy, a megajoule or more, this chemical fuel would have to be present in macroscopic amounts. In fact, in many cases the volume of ash would greatly exceed the entire cell volume. These issues of energy storage and chemical fuel hypotheses have been discussed in the literature exhaustively. See, for example, Ref. 4, section II.1.2.

References

1. McKubre, M.C.H., et al. Isothermal Flow Calorimetric Investigations of the D/Pd System. in Second Annual Conference on Cold Fusion, "The Science of Cold Fusion". 1991. Como, Italy: Societa Italiana di Fisica, Bologna, Italy, http://lenr-canr.org/acrobat/McKubreMCHisothermala.pdf

2. Kainthla, R.C., et al., Eight chemical explanations of the Fleischmann-Pons effect. J. Hydrogen Energy, 1989. 14(11): p. 771.

3. McKubre, M.C.H., et al., Development of Advanced Concepts for Nuclear Processes in Deuterated Metals. 1994, EPRI.

4. Storms, E., A Response to the Review of Cold Fusion by the DoE. 2005, Lattice Energy, LLC, http://lenr-canr.org/acrobat/StormsEaresponset.pdf

Other kinds of fusion

This article focuses on the Fleischmann-Pons effect produced in electrolytic cells. This effect has also been observed with other methods of forming hydrides such as gas loading, electromigration and ion implantion. Other forms of fusion have been studied by scientists. Some are "cold" in the sense that no part of the reaction is actually hot (except for the reaction products), some are "cold" in the sense that the energies required are low and the bulk of the material is at a relatively low temperature, and some are "hot", involving reactions which create macroscopic regions of very high temperature and pressure.

Locally cold fusion:

  • Muon-catalyzed fusion is a well-established and reproducible fusion process which occurs at ordinary temperatures. It has been studied in detail by Steven Jones in the early 1980s. Because of the energy required to create muons and the fact that muons have limited lifetimes, it is not currently able to produce net energy, and analyses indicate at present that energy production from the reaction is not possible.

Generally cold, locally hot fusion:

  • Pyroelectric fusion was reported in April 2005 by a team at UCLA. This process uses a pyroelectric crystal to generate a powerful electric field (in the range of gigavolts per metre), which ionises deuterium atoms and accelerates the ions into a solid target containing deuterium. The experimenters reported that this resulted in fusion, but not a net energy production.
  • The Farnsworth-Hirsch Fusor is a tabletop device in which fusion occurs. This fusion comes from high effective temperatures produced by electrostatic acceleration of ions. The device can be built inexpensively, but it too is unable to produce a net power output. These devices have a valid use however, and are commercially sold as a source of neutrons.
  • Antimatter-initialized fusion uses small amounts of antimatter to trigger a tiny fusion explosion. This has been studied primarily in the context of making nuclear pulse propulsion feasible. This is not near becoming a practical power source, due to the cost of manufacturing antimatter alone.
  • In sonoluminescence, acoustic shock waves create temporary bubbles that collapse shortly after creation, producing very high temperatures and pressures. In 2002, Rusi P. Taleyarkhan reported the possibility that bubble fusion occurs in those collapsing bubbles. As of 2005, experiments to determine whether fusion is occurring give conflicting results. If fusion is occurring, it is because the temperature and pressure are sufficiently high to produce hot fusion.

Hot fusion:

Several of these systems are "nonequilibrium systems", in which very high temperatures and pressures are produced in a relatively small region adjacent to material of much lower temperature. In his doctoral thesis for Massachusetts Institute of Technology, Todd Rider did a theoretical study of all non-equilibrium fusion systems. He demonstrated that all such systems will leak energy at a rapid rate due to Bremsstrahlung, radiation produced when electrons in the plasma hit other electrons or ions at a cooler temperature and suddenly decelerate. The problem is not as pronounced in a hot plasma because the range of temperatures, and thus the magnitude of the deceleration, is much lower.

See also

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Energy Directory

References

  • Krivit, Steven ; Winocur, Nadine. The Rebirth of Cold Fusion. Los Angeles, CA, Pacific Oaks Press, 2004 ISBN 0976054582.
    • A book documenting the cold fusion saga from a "pro-cold fusion" perspective, backed with research and interviews from cold fusion researchers around the world.
  • Beaudette, Charles. Excess Heat: Why Cold Fusion Research Prevailed. Concord, N.H.: Infinite Energy Press, 2000. ISBN 0967854814.
    • A more recent scientific account defending the view that cold fusion research prevailed.
  • Close, Frank E..Too Hot to Handle: The Race for Cold Fusion. Princeton, N.J. : Princeton University Press, 1991. ISBN 0691085919; ISBN 0140159266.
  • Huizenga, John R. Cold Fusion: The Scientific Fiasco of the Century. Rochester, N.Y.: University of Rochester Press, 1992. ISBN 1878822071; ISBN 0198558171.
    • The above two books are other skeptical examinations from the scientific mainstream. Huizenga was co-chair of the DOE panel set up to investigate the Pons/Fleischmann experiment, and his book is perhaps the definitive account of the cold fusion affair.
  • Mallove, Eugene. Fire from Ice. Concord, N.H.: Infinite Energy Press, 1991. ISBN 1892925028.
    • An early account from the pro-cold-fusion perspective.
  • Park, Robert L. Voodoo Science: The Road from Foolishness to Fraud. New York: Oxford University Press, 2000. ISBN 0195135156.
    • Park gives a thorough account of cold fusion and its history, which account represents the perspective of the mainstream scientific community.

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